Closures for containers

ABSTRACT

A closure for the neck of a container, which closure is moulded as a unitary structure from a resilient material and comprises a top portion, a screw-threaded annular skirt portion and a downwardly depending annulus provided on the underside of the top portion, wherein a sloping portion, having an inside surface which is at least partially convex in shape, joins the top portion to the skirt portion, and the downwardly depending annulus has a concave external face.

nited States Patent inventors Edmund Philip Adcoek llarpenden;

Jeffrey Herbert Sutcliffe, Norwich, Norfolk; Colin Charles Woodward, Maidenhead, all of, England 819,381

Apr. 25. 1969 July 27, 1971 U.G. Closurers and Plastics Limited Norfolk, England Apr. 26, 1968 Great Britain Appl. No. Filed Patented Assignee Priority CLOSURES FOR CONTAINERS 5 Claims, 2 Drawing Figs.

US. Cl. 215/40, 215/43 R Int. Cl. 865d 41/04 Field Search 2l5/40,41,

[5 6] Reierences Cited UNlTED STATES PATENTS 2,914,206 11/1959 Lowen 215/41 2,965,256 12/1960 Yochem. 215/43 3,482,725 12/1969 Exton 215/43 FOREIGN PATENTS 1,049,059 8/1953 France 215/43 1,004,277 9/1965 Great Britain 215/43 Primary Examiner- Donald F. Norton Attorney-Cushman, Darby & Cushman ABSTRACT: A closure for the neck of a container, which closure is moulded as a unitary structure from a resilient material and comprises a top portion, a screw-threaded annular skirt portion and a downwardly depending annulus provided on the underside of the top portion, wherein a sloping portion, having an inside surface which is at least partially convex in shape, joins the top portion to the skirt portion, and the downwardly depending annulus has a concave external face.

PATENTEnJuLemn 3,595,418

SHEET 1 OF 2 4 1e: Woodward MAM/1.024% Cash nan Afforny CLOSURES FOR CONTAINERS This invention relates to closuresfor containers, for example bottle and jars, and is especially concerned with closures of the type which are applied to containers without the need for a separate liner or wad within the closure. Such closures are commonly referred to as wadless" closures.

According to the present invention a closure for the neck of a container is moulded as a unitary structure from a resilient natural or synthetic material and comprises atop portion, a screw-threaded annular skirt portion, a downwardly depending annulus having a concave external face provided on the underside of the top portion, and a sloping portion, having an inside surface which is at least partially convex in shape, joining the top portion to the skirt portion. The closure may be moulded from any suitable flexible or resilient material, for example rubber (natural or synthetic), polyethylene or polyvinyl chloride, but preferablyit is made from polypropylene. The screw thread provided on the skirt portion for engaging the neck of a container to which the clo sure is applied and gradually tightening the closure thereon, is preferably a single-start screw thread which engages a corresponding thread formed on the neck of the container. The screw thread may, however, be a multistart thread or a series of lugs adapted to engage corresponding sloping projections provided on the exterior of the container neck.

The downwardly depending annulus provided on the underside of the top portion of the closure, which may comprise a straight-sidedinternal face, suitably sloping at an angle of about to the longitudinal axis of the closure and a bottom face parallel with the top portion, will be so designed that, when the closure is applied to the neck of a container, pres sure of the outside edge of the container mouth against the convex surface of the sloping portion will cause the concave outer surface of the annulus to move towards the sloping portion, and hence will press the concave outer face of the annulus into sealing contact with the inside edge of the container mouth. It will be appreciated, therefore, that the sloping portion and the annulus act on the mouth of the container'after the manner of pincers. The harder the mouth of the container is pressed against the inside surface of the sloping portion, the tighter is the concave outer face of the annulus pressed against the inside of the container mouth.

The sloping portion of the closure joining the top portion to radius of curvature of the concavev external face of the downwardly depending annulus.

The invention is illustrated by means of the accompanying drawings, in which v i FIG. 1 is a sectional elevation of a closure according to the inventiomand 7 FIG. 2 is a sectional elevation of the closure of FIG. 1 applied to a container neck.

The closure, moulded from a resilient material such as polypropylene, comprises a top portion 1, an annular skirt portion 2 provided with an internal screw thread 3,-and a frustoconical portion 4 joining the top portion to the skirt portion. The underside of the top portion is provided with a downwardly depending substantial annulus 5, having a straight-sided internal face 6, which slopes at an angle of about l0 to the longitudinal axis of the closure, a bottom face 7 which is parallel with the top portion 1, and a concave external face 8.

The inside surface of the joining portion 4 is convexly curved, as indicated at 9. 1n the closure shown in the'drawing the inside surface of the joining portion is curved along about three-fourths of its length. The radius of curvature of the con- Vex surface 9 is substantially equal to the radius of curvature of the face 8 of annulus 5.

When the closure is applied to the neck 20 of a container having a corresponding screw thread and is screwed down tight (see FIG. 2), the outside radiused edge of the container mouth is pressed tightly against the convex portion 9. This pressure tends to move the portion 4 of the closure upwardly, and causes the annulus 5 to flex outwardly. This brings the concave face of annulus 5 into tight sealing contact with the inside of the container mouth, and a double seal is obtained, i.e. on both the inside and outside of the container mouth. The tighter the closure is applied to the container the tighter is the annulus 5 pressed into sealing contact with the inside of the container mouth.

In a specific example, a closure has the following dimensions (see FIG. 1):

Dimension a 0.95 inch;

Dimension b 0.18 inch;

Dimension c 0.21 inch;

Dimension 0' 0.04 inch;

Dimension 2 0.025 inch;

Dimension f 0.05 inch;

Dimension Dimension g 0.15 inch;

Dimension h 0.02 inch;

Dimension i0.03 inch.

The radius of curvature of the two curved faces 8 and 9 is 0.25 inch, and the radius of curvature of the curved part 10, joining faces 8 and 9, is 0.023 inch.

What we claim is:

l. A closure for the neck of a container, which closure is a unitary moulded structure of a resilient material, comprising a top portion, an internally screw-threaded annular skirt portion, which skirt portion is connected to said top portion by a sloping portion, and a downwardly depending annulus portion disposed on the underside of the top portion, said sloping portion having a convexly curved inside surface which joins the underside of the said top portion at a locus near the locus where an outer face of the said annulus portion joins the underside of said top portion, the outer face of said annulus portion having a concavely curved surface, the dimensions between the lower part of the convexly curved inside surface of the sloping portion and the lower part of the concavely curved surface of the outer face of the annulus portion being such as to receive the top of the mouth of a container but the dimension between the upper part of the convexly curved inside surface of the sloping portion and the upper part of the concavely curved surface of the outer face of the annulus portion being such that the top of the mouth of a container is tightly engaged with both the said inside surface of the sloping portion and surface of the outer face of the annulus portion when the said screw-threaded skirt portion is engaged by the screw threads of the container mouth, whereby the convexly curved inside surface of the sloping portion is engaged by the outer top portion of the container mouth and moved upwardly and causes the outer face of the annulus portion to pivot outwardly and against the inside top portion of the container mouth and be tightly engaged thereby, and hence effecting a tight seal between the outer top portion of the container mouth and the convexly curved inside surface of the sloping portion and between the inside top portion of the container mouth and outer face of the annulus portion.

2. A closure according to claim 1 wherein the outside surface of the sloping portion is frustoconical in shape.

3. A closure according to claim 1 wherein the downwardly depending annulus has a straight-sided internal face and a bottom face parallel with the top portion.

4. A closure according to claim 3 wherein the internal face of the downwardly depending annulus slopes at an angle of about 10 to the longitudinal axis of the closure.

5. A closureaccording to claim 1 wherein the radius of curvature of the convex inside surface of the sloping portion is equal to the radius of curvature of the concave outer face of the downwardly depending annulus. 

1. A closure for the neck of a container, which closure is a unitary moulded structure of a resilient material, comprising a top portion, an internally screw-threaded annular skirt portion, which skirt portion is connected to said top portion by a sloping portion, and a downwardly depending annulus portion disposed on the underside of the top portion, said sloping portion having a convexly curved inside surface which joins the underside of the said top portion at a locus near the locus where an outer face of the said annulus portion joins the underside of said top portion, the outer face of said annulus portion having a concavely curved surface, the dimensions between the lower part of the convexly curved inside surface of the sloping portion and the lower part of the concavely curved surface of the outer face of the annulus portion being such as to receive the top of the mouth of a container but the dimension between the upper part of the convexly curved inside surface of the sloping portion and the upper part of the concavely curved surface of the outer face of the annulus portion being such that the top of the mouth of a container is tightly engaged with both the said inside surface of the sloping portion and surface of the outer face of the annulus portion when the said screw-threaded skirt portion is engaged by the screw threads of the container mouth, whereby tHe convexly curved inside surface of the sloping portion is engaged by the outer top portion of the container mouth and moved upwardly and causes the outer face of the annulus portion to pivot outwardly and against the inside top portion of the container mouth and be tightly engaged thereby, and hence effecting a tight seal between the outer top portion of the container mouth and the convexly curved inside surface of the sloping portion and between the inside top portion of the container mouth and outer face of the annulus portion.
 2. A closure according to claim 1 wherein the outside surface of the sloping portion is frustoconical in shape.
 3. A closure according to claim 1 wherein the downwardly depending annulus has a straight-sided internal face and a bottom face parallel with the top portion.
 4. A closure according to claim 3 wherein the internal face of the downwardly depending annulus slopes at an angle of about 10* to the longitudinal axis of the closure.
 5. A closure according to claim 1 wherein the radius of curvature of the convex inside surface of the sloping portion is equal to the radius of curvature of the concave outer face of the downwardly depending annulus. 